Heat pipe switch

Abstract

A thermal pipe switch includes a single vapor channel communicating with two parallel formed liquid channels. Each of the liquid channels is connected to a respective liquid channel in a dual heat sink assembly which thermally contacts a cryocooler. If a first cryocooler becomes operative, liquid in the heat pipe thermal switch will fill a liquid channel communicating with the heat sink liquid channel which thermally contacts an operative cryocooler. The other heat pipe thermal switch liquid channel is filled with vapor so as to thermally decouple its respectively connected thermal cooler from the system.

I claim: 
     
       1. A heat pipe switch comprising: a body;   a vapor channel formed in the body;   a first liquid channel formed in the body and continuously extending in parallel spaced relation to the vapor channel;   a first passageway existing between the vapor channel and first liquid channel;   a second liquid channel formed in the body and continuously extending in parallel spaced relationship to the vapor channel;   a second passageway existing between the vapor channel and the second liquid channel;   sufficient working fluid to fill only one liquid channel connected to an operative fluid cooler.   
     
     
       2. The structure set forth in claim 1 wherein the length of the vapor channel has grooves formed therein for wetting the wall of the vapor channel except for that portion of the vapor channel wall located directly between the passageways to the liquid channels. 
     
     
       3. The structure set forth in claim 2 wherein the vapor channel has a circular cross section. 
     
     
       4. The structure set forth in claim 3 wherein each liquid channel has a circular cross section and has an identical diameter which is less than that of the vapor channel. 
     
     
       5. A heat pipe cooling system for a detector focal plane structure comprising: a pair of cryocoolers;   first and second heat sinks connected at corresponding first ends thereof to a respective cryocooler, each heat sink having a vapor and a liquid channel formed therein; and   a heat pipe thermal switch thermally connected at one end thereof to the focal plane structure for picking up heat therefrom, the switch having   a body,   a vapor channel formed in the body and communicating with the vapor channels in the heat sinks,   a first liquid channel formed in the body and extending in parallel spaced relation to the switch vapor channel and serially communicating with the liquid channel in the first heat sink,   a first passageway existing between the vapor channel and first liquid channel of the switch,   a second liquid channel formed in the body and extending in parallel spaced relation to the switch vapor channel and serially communicating with the liquid channel in the second heat pipe,   a second passageway existing between the switch vapor channel and the switch second liquid channel,   sufficient working fluid to fill only one switch liquid channel and the liquid channel of one heat sink which is connected to an operative fluid cooler.   
     
     
       6. The structure set forth in claim 5 wherein the length of the vapor channels in the switch and heat sinks have grooves formed therein for wetting the wall of the vapor channels. 
     
     
       7. The structure set forth in claim 6 wherein each vapor and liquid channel has a circular cross section. 
     
     
       8. The structure set forth in claim 7 wherein each liquid channel of the switch has an identical diameter which is less than that of the switch vapor channel.